/usr/share/gocode/src/github.com/hashicorp/serf/serf/serf.go is in golang-github-hashicorp-serf-dev 0.7.0~ds1-1.
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import (
"bytes"
"encoding/base64"
"encoding/json"
"errors"
"fmt"
"io/ioutil"
"log"
"math/rand"
"net"
"strconv"
"sync"
"time"
"github.com/armon/go-metrics"
"github.com/hashicorp/go-msgpack/codec"
"github.com/hashicorp/memberlist"
"github.com/hashicorp/serf/coordinate"
)
// These are the protocol versions that Serf can _understand_. These are
// Serf-level protocol versions that are passed down as the delegate
// version to memberlist below.
const (
ProtocolVersionMin uint8 = 2
ProtocolVersionMax = 4
)
const (
// Used to detect if the meta data is tags
// or if it is a raw role
tagMagicByte uint8 = 255
)
var (
// FeatureNotSupported is returned if a feature cannot be used
// due to an older protocol version being used.
FeatureNotSupported = fmt.Errorf("Feature not supported")
)
func init() {
// Seed the random number generator
rand.Seed(time.Now().UnixNano())
}
// Serf is a single node that is part of a single cluster that gets
// events about joins/leaves/failures/etc. It is created with the Create
// method.
//
// All functions on the Serf structure are safe to call concurrently.
type Serf struct {
// The clocks for different purposes. These MUST be the first things
// in this struct due to Golang issue #599.
clock LamportClock
eventClock LamportClock
queryClock LamportClock
broadcasts *memberlist.TransmitLimitedQueue
config *Config
failedMembers []*memberState
leftMembers []*memberState
memberlist *memberlist.Memberlist
memberLock sync.RWMutex
members map[string]*memberState
// Circular buffers for recent intents, used
// in case we get the intent before the relevant event
recentLeave []nodeIntent
recentLeaveIndex int
recentJoin []nodeIntent
recentJoinIndex int
eventBroadcasts *memberlist.TransmitLimitedQueue
eventBuffer []*userEvents
eventJoinIgnore bool
eventMinTime LamportTime
eventLock sync.RWMutex
queryBroadcasts *memberlist.TransmitLimitedQueue
queryBuffer []*queries
queryMinTime LamportTime
queryResponse map[LamportTime]*QueryResponse
queryLock sync.RWMutex
logger *log.Logger
joinLock sync.Mutex
stateLock sync.Mutex
state SerfState
shutdownCh chan struct{}
snapshotter *Snapshotter
keyManager *KeyManager
coordClient *coordinate.Client
coordCache map[string]*coordinate.Coordinate
coordCacheLock sync.RWMutex
}
// SerfState is the state of the Serf instance.
type SerfState int
const (
SerfAlive SerfState = iota
SerfLeaving
SerfLeft
SerfShutdown
)
func (s SerfState) String() string {
switch s {
case SerfAlive:
return "alive"
case SerfLeaving:
return "leaving"
case SerfLeft:
return "left"
case SerfShutdown:
return "shutdown"
default:
return "unknown"
}
}
// Member is a single member of the Serf cluster.
type Member struct {
Name string
Addr net.IP
Port uint16
Tags map[string]string
Status MemberStatus
// The minimum, maximum, and current values of the protocol versions
// and delegate (Serf) protocol versions that each member can understand
// or is speaking.
ProtocolMin uint8
ProtocolMax uint8
ProtocolCur uint8
DelegateMin uint8
DelegateMax uint8
DelegateCur uint8
}
// MemberStatus is the state that a member is in.
type MemberStatus int
const (
StatusNone MemberStatus = iota
StatusAlive
StatusLeaving
StatusLeft
StatusFailed
)
func (s MemberStatus) String() string {
switch s {
case StatusNone:
return "none"
case StatusAlive:
return "alive"
case StatusLeaving:
return "leaving"
case StatusLeft:
return "left"
case StatusFailed:
return "failed"
default:
panic(fmt.Sprintf("unknown MemberStatus: %d", s))
}
}
// memberState is used to track members that are no longer active due to
// leaving, failing, partitioning, etc. It tracks the member along with
// when that member was marked as leaving.
type memberState struct {
Member
statusLTime LamportTime // lamport clock time of last received message
leaveTime time.Time // wall clock time of leave
}
// nodeIntent is used to buffer intents for out-of-order deliveries
type nodeIntent struct {
LTime LamportTime
Node string
}
// userEvent is used to buffer events to prevent re-delivery
type userEvent struct {
Name string
Payload []byte
}
func (ue *userEvent) Equals(other *userEvent) bool {
if ue.Name != other.Name {
return false
}
if bytes.Compare(ue.Payload, other.Payload) != 0 {
return false
}
return true
}
// userEvents stores all the user events at a specific time
type userEvents struct {
LTime LamportTime
Events []userEvent
}
// queries stores all the query ids at a specific time
type queries struct {
LTime LamportTime
QueryIDs []uint32
}
const (
UserEventSizeLimit = 512 // Maximum byte size for event name and payload
snapshotSizeLimit = 128 * 1024 // Maximum 128 KB snapshot
)
// Create creates a new Serf instance, starting all the background tasks
// to maintain cluster membership information.
//
// After calling this function, the configuration should no longer be used
// or modified by the caller.
func Create(conf *Config) (*Serf, error) {
conf.Init()
if conf.ProtocolVersion < ProtocolVersionMin {
return nil, fmt.Errorf("Protocol version '%d' too low. Must be in range: [%d, %d]",
conf.ProtocolVersion, ProtocolVersionMin, ProtocolVersionMax)
} else if conf.ProtocolVersion > ProtocolVersionMax {
return nil, fmt.Errorf("Protocol version '%d' too high. Must be in range: [%d, %d]",
conf.ProtocolVersion, ProtocolVersionMin, ProtocolVersionMax)
}
serf := &Serf{
config: conf,
logger: log.New(conf.LogOutput, "", log.LstdFlags),
members: make(map[string]*memberState),
queryResponse: make(map[LamportTime]*QueryResponse),
shutdownCh: make(chan struct{}),
state: SerfAlive,
}
// Check that the meta data length is okay
if len(serf.encodeTags(conf.Tags)) > memberlist.MetaMaxSize {
return nil, fmt.Errorf("Encoded length of tags exceeds limit of %d bytes", memberlist.MetaMaxSize)
}
// Check if serf member event coalescing is enabled
if conf.CoalescePeriod > 0 && conf.QuiescentPeriod > 0 && conf.EventCh != nil {
c := &memberEventCoalescer{
lastEvents: make(map[string]EventType),
latestEvents: make(map[string]coalesceEvent),
}
conf.EventCh = coalescedEventCh(conf.EventCh, serf.shutdownCh,
conf.CoalescePeriod, conf.QuiescentPeriod, c)
}
// Check if user event coalescing is enabled
if conf.UserCoalescePeriod > 0 && conf.UserQuiescentPeriod > 0 && conf.EventCh != nil {
c := &userEventCoalescer{
events: make(map[string]*latestUserEvents),
}
conf.EventCh = coalescedEventCh(conf.EventCh, serf.shutdownCh,
conf.UserCoalescePeriod, conf.UserQuiescentPeriod, c)
}
// Listen for internal Serf queries. This is setup before the snapshotter, since
// we want to capture the query-time, but the internal listener does not passthrough
// the queries
outCh, err := newSerfQueries(serf, serf.logger, conf.EventCh, serf.shutdownCh)
if err != nil {
return nil, fmt.Errorf("Failed to setup serf query handler: %v", err)
}
conf.EventCh = outCh
// Set up network coordinate client.
if !conf.DisableCoordinates {
serf.coordClient, err = coordinate.NewClient(coordinate.DefaultConfig())
if err != nil {
return nil, fmt.Errorf("Failed to create coordinate client: %v", err)
}
}
// Try access the snapshot
var oldClock, oldEventClock, oldQueryClock LamportTime
var prev []*PreviousNode
if conf.SnapshotPath != "" {
eventCh, snap, err := NewSnapshotter(
conf.SnapshotPath,
snapshotSizeLimit,
conf.RejoinAfterLeave,
serf.logger,
&serf.clock,
serf.coordClient,
conf.EventCh,
serf.shutdownCh)
if err != nil {
return nil, fmt.Errorf("Failed to setup snapshot: %v", err)
}
serf.snapshotter = snap
conf.EventCh = eventCh
prev = snap.AliveNodes()
oldClock = snap.LastClock()
oldEventClock = snap.LastEventClock()
oldQueryClock = snap.LastQueryClock()
serf.eventMinTime = oldEventClock + 1
serf.queryMinTime = oldQueryClock + 1
}
// Set up the coordinate cache. We do this after we read the snapshot to
// make sure we get a good initial value from there, if we got one.
if !conf.DisableCoordinates {
serf.coordCache = make(map[string]*coordinate.Coordinate)
serf.coordCache[conf.NodeName] = serf.coordClient.GetCoordinate()
}
// Setup the various broadcast queues, which we use to send our own
// custom broadcasts along the gossip channel.
serf.broadcasts = &memberlist.TransmitLimitedQueue{
NumNodes: func() int {
return len(serf.members)
},
RetransmitMult: conf.MemberlistConfig.RetransmitMult,
}
serf.eventBroadcasts = &memberlist.TransmitLimitedQueue{
NumNodes: func() int {
return len(serf.members)
},
RetransmitMult: conf.MemberlistConfig.RetransmitMult,
}
serf.queryBroadcasts = &memberlist.TransmitLimitedQueue{
NumNodes: func() int {
return len(serf.members)
},
RetransmitMult: conf.MemberlistConfig.RetransmitMult,
}
// Create the buffer for recent intents
serf.recentJoin = make([]nodeIntent, conf.RecentIntentBuffer)
serf.recentLeave = make([]nodeIntent, conf.RecentIntentBuffer)
// Create a buffer for events and queries
serf.eventBuffer = make([]*userEvents, conf.EventBuffer)
serf.queryBuffer = make([]*queries, conf.QueryBuffer)
// Ensure our lamport clock is at least 1, so that the default
// join LTime of 0 does not cause issues
serf.clock.Increment()
serf.eventClock.Increment()
serf.queryClock.Increment()
// Restore the clock from snap if we have one
serf.clock.Witness(oldClock)
serf.eventClock.Witness(oldEventClock)
serf.queryClock.Witness(oldQueryClock)
// Modify the memberlist configuration with keys that we set
conf.MemberlistConfig.Events = &eventDelegate{serf: serf}
conf.MemberlistConfig.Conflict = &conflictDelegate{serf: serf}
conf.MemberlistConfig.Delegate = &delegate{serf: serf}
conf.MemberlistConfig.DelegateProtocolVersion = conf.ProtocolVersion
conf.MemberlistConfig.DelegateProtocolMin = ProtocolVersionMin
conf.MemberlistConfig.DelegateProtocolMax = ProtocolVersionMax
conf.MemberlistConfig.Name = conf.NodeName
conf.MemberlistConfig.ProtocolVersion = ProtocolVersionMap[conf.ProtocolVersion]
if !conf.DisableCoordinates {
conf.MemberlistConfig.Ping = &pingDelegate{serf: serf}
}
// Setup a merge delegate if necessary
if conf.Merge != nil {
md := &mergeDelegate{serf: serf}
conf.MemberlistConfig.Merge = md
conf.MemberlistConfig.Alive = md
}
// Create the underlying memberlist that will manage membership
// and failure detection for the Serf instance.
memberlist, err := memberlist.Create(conf.MemberlistConfig)
if err != nil {
return nil, fmt.Errorf("Failed to create memberlist: %v", err)
}
serf.memberlist = memberlist
// Create a key manager for handling all encryption key changes
serf.keyManager = &KeyManager{serf: serf}
// Start the background tasks. See the documentation above each method
// for more information on their role.
go serf.handleReap()
go serf.handleReconnect()
go serf.checkQueueDepth("Intent", serf.broadcasts)
go serf.checkQueueDepth("Event", serf.eventBroadcasts)
go serf.checkQueueDepth("Query", serf.queryBroadcasts)
// Attempt to re-join the cluster if we have known nodes
if len(prev) != 0 {
go serf.handleRejoin(prev)
}
return serf, nil
}
// ProtocolVersion returns the current protocol version in use by Serf.
// This is the Serf protocol version, not the memberlist protocol version.
func (s *Serf) ProtocolVersion() uint8 {
return s.config.ProtocolVersion
}
// EncryptionEnabled is a predicate that determines whether or not encryption
// is enabled, which can be possible in one of 2 cases:
// - Single encryption key passed at agent start (no persistence)
// - Keyring file provided at agent start
func (s *Serf) EncryptionEnabled() bool {
return s.config.MemberlistConfig.Keyring != nil
}
// KeyManager returns the key manager for the current Serf instance.
func (s *Serf) KeyManager() *KeyManager {
return s.keyManager
}
// UserEvent is used to broadcast a custom user event with a given
// name and payload. The events must be fairly small, and if the
// size limit is exceeded and error will be returned. If coalesce is enabled,
// nodes are allowed to coalesce this event. Coalescing is only available
// starting in v0.2
func (s *Serf) UserEvent(name string, payload []byte, coalesce bool) error {
// Check the size limit
if len(name)+len(payload) > UserEventSizeLimit {
return fmt.Errorf("user event exceeds limit of %d bytes", UserEventSizeLimit)
}
// Create a message
msg := messageUserEvent{
LTime: s.eventClock.Time(),
Name: name,
Payload: payload,
CC: coalesce,
}
s.eventClock.Increment()
// Process update locally
s.handleUserEvent(&msg)
// Start broadcasting the event
raw, err := encodeMessage(messageUserEventType, &msg)
if err != nil {
return err
}
s.eventBroadcasts.QueueBroadcast(&broadcast{
msg: raw,
})
return nil
}
// Query is used to broadcast a new query. The query must be fairly small,
// and an error will be returned if the size limit is exceeded. This is only
// available with protocol version 4 and newer. Query parameters are optional,
// and if not provided, a sane set of defaults will be used.
func (s *Serf) Query(name string, payload []byte, params *QueryParam) (*QueryResponse, error) {
// Check that the latest protocol is in use
if s.ProtocolVersion() < 4 {
return nil, FeatureNotSupported
}
// Provide default parameters if none given
if params == nil {
params = s.DefaultQueryParams()
} else if params.Timeout == 0 {
params.Timeout = s.DefaultQueryTimeout()
}
// Get the local node
local := s.memberlist.LocalNode()
// Encode the filters
filters, err := params.encodeFilters()
if err != nil {
return nil, fmt.Errorf("Failed to format filters: %v", err)
}
// Setup the flags
var flags uint32
if params.RequestAck {
flags |= queryFlagAck
}
// Create a message
q := messageQuery{
LTime: s.queryClock.Time(),
ID: uint32(rand.Int31()),
Addr: local.Addr,
Port: local.Port,
Filters: filters,
Flags: flags,
Timeout: params.Timeout,
Name: name,
Payload: payload,
}
// Encode the query
raw, err := encodeMessage(messageQueryType, &q)
if err != nil {
return nil, err
}
// Check the size
if len(raw) > s.config.QuerySizeLimit {
return nil, fmt.Errorf("query exceeds limit of %d bytes", s.config.QuerySizeLimit)
}
// Register QueryResponse to track acks and responses
resp := newQueryResponse(s.memberlist.NumMembers(), &q)
s.registerQueryResponse(params.Timeout, resp)
// Process query locally
s.handleQuery(&q)
// Start broadcasting the event
s.queryBroadcasts.QueueBroadcast(&broadcast{
msg: raw,
})
return resp, nil
}
// registerQueryResponse is used to setup the listeners for the query,
// and to schedule closing the query after the timeout.
func (s *Serf) registerQueryResponse(timeout time.Duration, resp *QueryResponse) {
s.queryLock.Lock()
defer s.queryLock.Unlock()
// Map the LTime to the QueryResponse. This is necessarily 1-to-1,
// since we increment the time for each new query.
s.queryResponse[resp.lTime] = resp
// Setup a timer to close the response and deregister after the timeout
time.AfterFunc(timeout, func() {
s.queryLock.Lock()
delete(s.queryResponse, resp.lTime)
resp.Close()
s.queryLock.Unlock()
})
}
// SetTags is used to dynamically update the tags associated with
// the local node. This will propagate the change to the rest of
// the cluster. Blocks until a the message is broadcast out.
func (s *Serf) SetTags(tags map[string]string) error {
// Check that the meta data length is okay
if len(s.encodeTags(tags)) > memberlist.MetaMaxSize {
return fmt.Errorf("Encoded length of tags exceeds limit of %d bytes",
memberlist.MetaMaxSize)
}
// Update the config
s.config.Tags = tags
// Trigger a memberlist update
return s.memberlist.UpdateNode(s.config.BroadcastTimeout)
}
// Join joins an existing Serf cluster. Returns the number of nodes
// successfully contacted. The returned error will be non-nil only in the
// case that no nodes could be contacted. If ignoreOld is true, then any
// user messages sent prior to the join will be ignored.
func (s *Serf) Join(existing []string, ignoreOld bool) (int, error) {
// Do a quick state check
if s.State() != SerfAlive {
return 0, fmt.Errorf("Serf can't Join after Leave or Shutdown")
}
// Hold the joinLock, this is to make eventJoinIgnore safe
s.joinLock.Lock()
defer s.joinLock.Unlock()
// Ignore any events from a potential join. This is safe since we hold
// the joinLock and nobody else can be doing a Join
if ignoreOld {
s.eventJoinIgnore = true
defer func() {
s.eventJoinIgnore = false
}()
}
// Have memberlist attempt to join
num, err := s.memberlist.Join(existing)
// If we joined any nodes, broadcast the join message
if num > 0 {
// Start broadcasting the update
if err := s.broadcastJoin(s.clock.Time()); err != nil {
return num, err
}
}
return num, err
}
// broadcastJoin broadcasts a new join intent with a
// given clock value. It is used on either join, or if
// we need to refute an older leave intent. Cannot be called
// with the memberLock held.
func (s *Serf) broadcastJoin(ltime LamportTime) error {
// Construct message to update our lamport clock
msg := messageJoin{
LTime: ltime,
Node: s.config.NodeName,
}
s.clock.Witness(ltime)
// Process update locally
s.handleNodeJoinIntent(&msg)
// Start broadcasting the update
if err := s.broadcast(messageJoinType, &msg, nil); err != nil {
s.logger.Printf("[WARN] serf: Failed to broadcast join intent: %v", err)
return err
}
return nil
}
// Leave gracefully exits the cluster. It is safe to call this multiple
// times.
func (s *Serf) Leave() error {
// Check the current state
s.stateLock.Lock()
if s.state == SerfLeft {
s.stateLock.Unlock()
return nil
} else if s.state == SerfLeaving {
s.stateLock.Unlock()
return fmt.Errorf("Leave already in progress")
} else if s.state == SerfShutdown {
s.stateLock.Unlock()
return fmt.Errorf("Leave called after Shutdown")
}
s.state = SerfLeaving
s.stateLock.Unlock()
// If we have a snapshot, mark we are leaving
if s.snapshotter != nil {
s.snapshotter.Leave()
}
// Construct the message for the graceful leave
msg := messageLeave{
LTime: s.clock.Time(),
Node: s.config.NodeName,
}
s.clock.Increment()
// Process the leave locally
s.handleNodeLeaveIntent(&msg)
// Only broadcast the leave message if there is at least one
// other node alive.
if s.hasAliveMembers() {
notifyCh := make(chan struct{})
if err := s.broadcast(messageLeaveType, &msg, notifyCh); err != nil {
return err
}
select {
case <-notifyCh:
case <-time.After(s.config.BroadcastTimeout):
return errors.New("timeout while waiting for graceful leave")
}
}
// Attempt the memberlist leave
err := s.memberlist.Leave(s.config.BroadcastTimeout)
if err != nil {
return err
}
// Transition to Left only if we not already shutdown
s.stateLock.Lock()
if s.state != SerfShutdown {
s.state = SerfLeft
}
s.stateLock.Unlock()
return nil
}
// hasAliveMembers is called to check for any alive members other than
// ourself.
func (s *Serf) hasAliveMembers() bool {
s.memberLock.RLock()
defer s.memberLock.RUnlock()
hasAlive := false
for _, m := range s.members {
// Skip ourself, we want to know if OTHER members are alive
if m.Name == s.config.NodeName {
continue
}
if m.Status == StatusAlive {
hasAlive = true
break
}
}
return hasAlive
}
// LocalMember returns the Member information for the local node
func (s *Serf) LocalMember() Member {
s.memberLock.RLock()
defer s.memberLock.RUnlock()
return s.members[s.config.NodeName].Member
}
// Members returns a point-in-time snapshot of the members of this cluster.
func (s *Serf) Members() []Member {
s.memberLock.RLock()
defer s.memberLock.RUnlock()
members := make([]Member, 0, len(s.members))
for _, m := range s.members {
members = append(members, m.Member)
}
return members
}
// RemoveFailedNode forcibly removes a failed node from the cluster
// immediately, instead of waiting for the reaper to eventually reclaim it.
// This also has the effect that Serf will no longer attempt to reconnect
// to this node.
func (s *Serf) RemoveFailedNode(node string) error {
// Construct the message to broadcast
msg := messageLeave{
LTime: s.clock.Time(),
Node: node,
}
s.clock.Increment()
// Process our own event
s.handleNodeLeaveIntent(&msg)
// If we have no members, then we don't need to broadcast
if !s.hasAliveMembers() {
return nil
}
// Broadcast the remove
notifyCh := make(chan struct{})
if err := s.broadcast(messageLeaveType, &msg, notifyCh); err != nil {
return err
}
// Wait for the broadcast
select {
case <-notifyCh:
case <-time.After(s.config.BroadcastTimeout):
return fmt.Errorf("timed out broadcasting node removal")
}
return nil
}
// Shutdown forcefully shuts down the Serf instance, stopping all network
// activity and background maintenance associated with the instance.
//
// This is not a graceful shutdown, and should be preceded by a call
// to Leave. Otherwise, other nodes in the cluster will detect this node's
// exit as a node failure.
//
// It is safe to call this method multiple times.
func (s *Serf) Shutdown() error {
s.stateLock.Lock()
defer s.stateLock.Unlock()
if s.state == SerfShutdown {
return nil
}
if s.state != SerfLeft {
s.logger.Printf("[WARN] serf: Shutdown without a Leave")
}
s.state = SerfShutdown
close(s.shutdownCh)
err := s.memberlist.Shutdown()
if err != nil {
return err
}
// Wait for the snapshoter to finish if we have one
if s.snapshotter != nil {
s.snapshotter.Wait()
}
return nil
}
// ShutdownCh returns a channel that can be used to wait for
// Serf to shutdown.
func (s *Serf) ShutdownCh() <-chan struct{} {
return s.shutdownCh
}
// Memberlist is used to get access to the underlying Memberlist instance
func (s *Serf) Memberlist() *memberlist.Memberlist {
return s.memberlist
}
// State is the current state of this Serf instance.
func (s *Serf) State() SerfState {
s.stateLock.Lock()
defer s.stateLock.Unlock()
return s.state
}
// broadcast takes a Serf message type, encodes it for the wire, and queues
// the broadcast. If a notify channel is given, this channel will be closed
// when the broadcast is sent.
func (s *Serf) broadcast(t messageType, msg interface{}, notify chan<- struct{}) error {
raw, err := encodeMessage(t, msg)
if err != nil {
return err
}
s.broadcasts.QueueBroadcast(&broadcast{
msg: raw,
notify: notify,
})
return nil
}
// handleNodeJoin is called when a node join event is received
// from memberlist.
func (s *Serf) handleNodeJoin(n *memberlist.Node) {
s.memberLock.Lock()
defer s.memberLock.Unlock()
var oldStatus MemberStatus
member, ok := s.members[n.Name]
if !ok {
oldStatus = StatusNone
member = &memberState{
Member: Member{
Name: n.Name,
Addr: net.IP(n.Addr),
Port: n.Port,
Tags: s.decodeTags(n.Meta),
Status: StatusAlive,
},
}
// Check if we have a join intent and use the LTime
if join := recentIntent(s.recentJoin, n.Name); join != nil {
member.statusLTime = join.LTime
}
// Check if we have a leave intent
if leave := recentIntent(s.recentLeave, n.Name); leave != nil {
if leave.LTime > member.statusLTime {
member.Status = StatusLeaving
member.statusLTime = leave.LTime
}
}
s.members[n.Name] = member
} else {
oldStatus = member.Status
member.Status = StatusAlive
member.leaveTime = time.Time{}
member.Addr = net.IP(n.Addr)
member.Port = n.Port
member.Tags = s.decodeTags(n.Meta)
}
// Update the protocol versions every time we get an event
member.ProtocolMin = n.PMin
member.ProtocolMax = n.PMax
member.ProtocolCur = n.PCur
member.DelegateMin = n.DMin
member.DelegateMax = n.DMax
member.DelegateCur = n.DCur
// If node was previously in a failed state, then clean up some
// internal accounting.
// TODO(mitchellh): needs tests to verify not reaped
if oldStatus == StatusFailed || oldStatus == StatusLeft {
s.failedMembers = removeOldMember(s.failedMembers, member.Name)
s.leftMembers = removeOldMember(s.leftMembers, member.Name)
}
// Update some metrics
metrics.IncrCounter([]string{"serf", "member", "join"}, 1)
// Send an event along
s.logger.Printf("[INFO] serf: EventMemberJoin: %s %s",
member.Member.Name, member.Member.Addr)
if s.config.EventCh != nil {
s.config.EventCh <- MemberEvent{
Type: EventMemberJoin,
Members: []Member{member.Member},
}
}
}
// handleNodeLeave is called when a node leave event is received
// from memberlist.
func (s *Serf) handleNodeLeave(n *memberlist.Node) {
s.memberLock.Lock()
defer s.memberLock.Unlock()
member, ok := s.members[n.Name]
if !ok {
// We've never even heard of this node that is supposedly
// leaving. Just ignore it completely.
return
}
switch member.Status {
case StatusLeaving:
member.Status = StatusLeft
member.leaveTime = time.Now()
s.leftMembers = append(s.leftMembers, member)
case StatusAlive:
member.Status = StatusFailed
member.leaveTime = time.Now()
s.failedMembers = append(s.failedMembers, member)
default:
// Unknown state that it was in? Just don't do anything
s.logger.Printf("[WARN] serf: Bad state when leave: %d", member.Status)
return
}
// Send an event along
event := EventMemberLeave
eventStr := "EventMemberLeave"
if member.Status != StatusLeft {
event = EventMemberFailed
eventStr = "EventMemberFailed"
}
// Update some metrics
metrics.IncrCounter([]string{"serf", "member", member.Status.String()}, 1)
s.logger.Printf("[INFO] serf: %s: %s %s",
eventStr, member.Member.Name, member.Member.Addr)
if s.config.EventCh != nil {
s.config.EventCh <- MemberEvent{
Type: event,
Members: []Member{member.Member},
}
}
}
// handleNodeUpdate is called when a node meta data update
// has taken place
func (s *Serf) handleNodeUpdate(n *memberlist.Node) {
s.memberLock.Lock()
defer s.memberLock.Unlock()
member, ok := s.members[n.Name]
if !ok {
// We've never even heard of this node that is updating.
// Just ignore it completely.
return
}
// Update the member attributes
member.Addr = net.IP(n.Addr)
member.Port = n.Port
member.Tags = s.decodeTags(n.Meta)
// Snag the latest versions. NOTE - the current memberlist code will NOT
// fire an update event if the metadata (for Serf, tags) stays the same
// and only the protocol versions change. If we wake any Serf-level
// protocol changes where we want to get this event under those
// circumstances, we will need to update memberlist to do a check of
// versions as well as the metadata.
member.ProtocolMin = n.PMin
member.ProtocolMax = n.PMax
member.ProtocolCur = n.PCur
member.DelegateMin = n.DMin
member.DelegateMax = n.DMax
member.DelegateCur = n.DCur
// Update some metrics
metrics.IncrCounter([]string{"serf", "member", "update"}, 1)
// Send an event along
s.logger.Printf("[INFO] serf: EventMemberUpdate: %s", member.Member.Name)
if s.config.EventCh != nil {
s.config.EventCh <- MemberEvent{
Type: EventMemberUpdate,
Members: []Member{member.Member},
}
}
}
// handleNodeLeaveIntent is called when an intent to leave is received.
func (s *Serf) handleNodeLeaveIntent(leaveMsg *messageLeave) bool {
// Witness a potentially newer time
s.clock.Witness(leaveMsg.LTime)
s.memberLock.Lock()
defer s.memberLock.Unlock()
member, ok := s.members[leaveMsg.Node]
if !ok {
// If we've already seen this message don't rebroadcast
if recentIntent(s.recentLeave, leaveMsg.Node) != nil {
return false
}
// We don't know this member so store it in a buffer for now
s.recentLeave[s.recentLeaveIndex] = nodeIntent{
LTime: leaveMsg.LTime,
Node: leaveMsg.Node,
}
s.recentLeaveIndex = (s.recentLeaveIndex + 1) % len(s.recentLeave)
return true
}
// If the message is old, then it is irrelevant and we can skip it
if leaveMsg.LTime <= member.statusLTime {
return false
}
// Refute us leaving if we are in the alive state
// Must be done in another goroutine since we have the memberLock
if leaveMsg.Node == s.config.NodeName && s.state == SerfAlive {
s.logger.Printf("[DEBUG] serf: Refuting an older leave intent")
go s.broadcastJoin(s.clock.Time())
return false
}
// State transition depends on current state
switch member.Status {
case StatusAlive:
member.Status = StatusLeaving
member.statusLTime = leaveMsg.LTime
return true
case StatusFailed:
member.Status = StatusLeft
member.statusLTime = leaveMsg.LTime
// Remove from the failed list and add to the left list. We add
// to the left list so that when we do a sync, other nodes will
// remove it from their failed list.
s.failedMembers = removeOldMember(s.failedMembers, member.Name)
s.leftMembers = append(s.leftMembers, member)
// We must push a message indicating the node has now
// left to allow higher-level applications to handle the
// graceful leave.
s.logger.Printf("[INFO] serf: EventMemberLeave (forced): %s %s",
member.Member.Name, member.Member.Addr)
if s.config.EventCh != nil {
s.config.EventCh <- MemberEvent{
Type: EventMemberLeave,
Members: []Member{member.Member},
}
}
return true
default:
return false
}
}
// handleNodeJoinIntent is called when a node broadcasts a
// join message to set the lamport time of its join
func (s *Serf) handleNodeJoinIntent(joinMsg *messageJoin) bool {
// Witness a potentially newer time
s.clock.Witness(joinMsg.LTime)
s.memberLock.Lock()
defer s.memberLock.Unlock()
member, ok := s.members[joinMsg.Node]
if !ok {
// If we've already seen this message don't rebroadcast
if recentIntent(s.recentJoin, joinMsg.Node) != nil {
return false
}
// We don't know this member so store it in a buffer for now
s.recentJoin[s.recentJoinIndex] = nodeIntent{LTime: joinMsg.LTime, Node: joinMsg.Node}
s.recentJoinIndex = (s.recentJoinIndex + 1) % len(s.recentJoin)
return true
}
// Check if this time is newer than what we have
if joinMsg.LTime <= member.statusLTime {
return false
}
// Update the LTime
member.statusLTime = joinMsg.LTime
// If we are in the leaving state, we should go back to alive,
// since the leaving message must have been for an older time
if member.Status == StatusLeaving {
member.Status = StatusAlive
}
return true
}
// handleUserEvent is called when a user event broadcast is
// received. Returns if the message should be rebroadcast.
func (s *Serf) handleUserEvent(eventMsg *messageUserEvent) bool {
// Witness a potentially newer time
s.eventClock.Witness(eventMsg.LTime)
s.eventLock.Lock()
defer s.eventLock.Unlock()
// Ignore if it is before our minimum event time
if eventMsg.LTime < s.eventMinTime {
return false
}
// Check if this message is too old
curTime := s.eventClock.Time()
if curTime > LamportTime(len(s.eventBuffer)) &&
eventMsg.LTime < curTime-LamportTime(len(s.eventBuffer)) {
s.logger.Printf(
"[WARN] serf: received old event %s from time %d (current: %d)",
eventMsg.Name,
eventMsg.LTime,
s.eventClock.Time())
return false
}
// Check if we've already seen this
idx := eventMsg.LTime % LamportTime(len(s.eventBuffer))
seen := s.eventBuffer[idx]
userEvent := userEvent{Name: eventMsg.Name, Payload: eventMsg.Payload}
if seen != nil && seen.LTime == eventMsg.LTime {
for _, previous := range seen.Events {
if previous.Equals(&userEvent) {
return false
}
}
} else {
seen = &userEvents{LTime: eventMsg.LTime}
s.eventBuffer[idx] = seen
}
// Add to recent events
seen.Events = append(seen.Events, userEvent)
// Update some metrics
metrics.IncrCounter([]string{"serf", "events"}, 1)
metrics.IncrCounter([]string{"serf", "events", eventMsg.Name}, 1)
if s.config.EventCh != nil {
s.config.EventCh <- UserEvent{
LTime: eventMsg.LTime,
Name: eventMsg.Name,
Payload: eventMsg.Payload,
Coalesce: eventMsg.CC,
}
}
return true
}
// handleQuery is called when a query broadcast is
// received. Returns if the message should be rebroadcast.
func (s *Serf) handleQuery(query *messageQuery) bool {
// Witness a potentially newer time
s.queryClock.Witness(query.LTime)
s.queryLock.Lock()
defer s.queryLock.Unlock()
// Ignore if it is before our minimum query time
if query.LTime < s.queryMinTime {
return false
}
// Check if this message is too old
curTime := s.queryClock.Time()
if curTime > LamportTime(len(s.queryBuffer)) &&
query.LTime < curTime-LamportTime(len(s.queryBuffer)) {
s.logger.Printf(
"[WARN] serf: received old query %s from time %d (current: %d)",
query.Name,
query.LTime,
s.queryClock.Time())
return false
}
// Check if we've already seen this
idx := query.LTime % LamportTime(len(s.queryBuffer))
seen := s.queryBuffer[idx]
if seen != nil && seen.LTime == query.LTime {
for _, previous := range seen.QueryIDs {
if previous == query.ID {
// Seen this ID already
return false
}
}
} else {
seen = &queries{LTime: query.LTime}
s.queryBuffer[idx] = seen
}
// Add to recent queries
seen.QueryIDs = append(seen.QueryIDs, query.ID)
// Update some metrics
metrics.IncrCounter([]string{"serf", "queries"}, 1)
metrics.IncrCounter([]string{"serf", "queries", query.Name}, 1)
// Check if we should rebroadcast, this may be disabled by a flag
rebroadcast := true
if query.NoBroadcast() {
rebroadcast = false
}
// Filter the query
if !s.shouldProcessQuery(query.Filters) {
// Even if we don't process it further, we should rebroadcast,
// since it is the first time we've seen this.
return rebroadcast
}
// Send ack if requested, without waiting for client to Respond()
if query.Ack() {
ack := messageQueryResponse{
LTime: query.LTime,
ID: query.ID,
From: s.config.NodeName,
Flags: queryFlagAck,
}
raw, err := encodeMessage(messageQueryResponseType, &ack)
if err != nil {
s.logger.Printf("[ERR] serf: failed to format ack: %v", err)
} else {
addr := net.UDPAddr{IP: query.Addr, Port: int(query.Port)}
if err := s.memberlist.SendTo(&addr, raw); err != nil {
s.logger.Printf("[ERR] serf: failed to send ack: %v", err)
}
}
}
if s.config.EventCh != nil {
s.config.EventCh <- &Query{
LTime: query.LTime,
Name: query.Name,
Payload: query.Payload,
serf: s,
id: query.ID,
addr: query.Addr,
port: query.Port,
deadline: time.Now().Add(query.Timeout),
}
}
return rebroadcast
}
// handleResponse is called when a query response is
// received.
func (s *Serf) handleQueryResponse(resp *messageQueryResponse) {
// Look for a corresponding QueryResponse
s.queryLock.RLock()
query, ok := s.queryResponse[resp.LTime]
s.queryLock.RUnlock()
if !ok {
s.logger.Printf("[WARN] serf: reply for non-running query (LTime: %d, ID: %d) From: %s",
resp.LTime, resp.ID, resp.From)
return
}
// Verify the ID matches
if query.id != resp.ID {
s.logger.Printf("[WARN] serf: query reply ID mismatch (Local: %d, Response: %d)",
query.id, resp.ID)
return
}
// Check if the query is closed
if query.Finished() {
return
}
// Process each type of response
if resp.Ack() {
metrics.IncrCounter([]string{"serf", "query_acks"}, 1)
select {
case query.ackCh <- resp.From:
default:
s.logger.Printf("[WARN] serf: Failed to delivery query ack, dropping")
}
} else {
metrics.IncrCounter([]string{"serf", "query_responses"}, 1)
select {
case query.respCh <- NodeResponse{From: resp.From, Payload: resp.Payload}:
default:
s.logger.Printf("[WARN] serf: Failed to delivery query response, dropping")
}
}
}
// handleNodeConflict is invoked when a join detects a conflict over a name.
// This means two different nodes (IP/Port) are claiming the same name. Memberlist
// will reject the "new" node mapping, but we can still be notified
func (s *Serf) handleNodeConflict(existing, other *memberlist.Node) {
// Log a basic warning if the node is not us...
if existing.Name != s.config.NodeName {
s.logger.Printf("[WARN] serf: Name conflict for '%s' both %s:%d and %s:%d are claiming",
existing.Name, existing.Addr, existing.Port, other.Addr, other.Port)
return
}
// The current node is conflicting! This is an error
s.logger.Printf("[ERR] serf: Node name conflicts with another node at %s:%d. Names must be unique! (Resolution enabled: %v)",
other.Addr, other.Port, s.config.EnableNameConflictResolution)
// If automatic resolution is enabled, kick off the resolution
if s.config.EnableNameConflictResolution {
go s.resolveNodeConflict()
}
}
// resolveNodeConflict is used to determine which node should remain during
// a name conflict. This is done by running an internal query.
func (s *Serf) resolveNodeConflict() {
// Get the local node
local := s.memberlist.LocalNode()
// Start a name resolution query
qName := internalQueryName(conflictQuery)
payload := []byte(s.config.NodeName)
resp, err := s.Query(qName, payload, nil)
if err != nil {
s.logger.Printf("[ERR] serf: Failed to start name resolution query: %v", err)
return
}
// Counter to determine winner
var responses, matching int
// Gather responses
respCh := resp.ResponseCh()
for r := range respCh {
// Decode the response
if len(r.Payload) < 1 || messageType(r.Payload[0]) != messageConflictResponseType {
s.logger.Printf("[ERR] serf: Invalid conflict query response type: %v", r.Payload)
continue
}
var member Member
if err := decodeMessage(r.Payload[1:], &member); err != nil {
s.logger.Printf("[ERR] serf: Failed to decode conflict query response: %v", err)
continue
}
// Update the counters
responses++
if bytes.Equal(member.Addr, local.Addr) && member.Port == local.Port {
matching++
}
}
// Query over, determine if we should live
majority := (responses / 2) + 1
if matching >= majority {
s.logger.Printf("[INFO] serf: majority in name conflict resolution [%d / %d]",
matching, responses)
return
}
// Since we lost the vote, we need to exit
s.logger.Printf("[WARN] serf: minority in name conflict resolution, quiting [%d / %d]",
matching, responses)
if err := s.Shutdown(); err != nil {
s.logger.Printf("[ERR] serf: Failed to shutdown: %v", err)
}
}
// handleReap periodically reaps the list of failed and left members.
func (s *Serf) handleReap() {
for {
select {
case <-time.After(s.config.ReapInterval):
s.memberLock.Lock()
s.failedMembers = s.reap(s.failedMembers, s.config.ReconnectTimeout)
s.leftMembers = s.reap(s.leftMembers, s.config.TombstoneTimeout)
s.memberLock.Unlock()
case <-s.shutdownCh:
return
}
}
}
// handleReconnect attempts to reconnect to recently failed nodes
// on configured intervals.
func (s *Serf) handleReconnect() {
for {
select {
case <-time.After(s.config.ReconnectInterval):
s.reconnect()
case <-s.shutdownCh:
return
}
}
}
// reap is called with a list of old members and a timeout, and removes
// members that have exceeded the timeout. The members are removed from
// both the old list and the members itself. Locking is left to the caller.
func (s *Serf) reap(old []*memberState, timeout time.Duration) []*memberState {
now := time.Now()
n := len(old)
for i := 0; i < n; i++ {
m := old[i]
// Skip if the timeout is not yet reached
if now.Sub(m.leaveTime) <= timeout {
continue
}
// Delete from the list
old[i], old[n-1] = old[n-1], nil
old = old[:n-1]
n--
i--
// Delete from members
delete(s.members, m.Name)
// Tell the coordinate client the node has gone away and delete
// its cached coordinates.
if !s.config.DisableCoordinates {
s.coordClient.ForgetNode(m.Name)
s.coordCacheLock.Lock()
delete(s.coordCache, m.Name)
s.coordCacheLock.Unlock()
}
// Send an event along
s.logger.Printf("[INFO] serf: EventMemberReap: %s", m.Name)
if s.config.EventCh != nil {
s.config.EventCh <- MemberEvent{
Type: EventMemberReap,
Members: []Member{m.Member},
}
}
}
return old
}
// reconnect attempts to reconnect to recently fail nodes.
func (s *Serf) reconnect() {
s.memberLock.RLock()
// Nothing to do if there are no failed members
n := len(s.failedMembers)
if n == 0 {
s.memberLock.RUnlock()
return
}
// Probability we should attempt to reconect is given
// by num failed / (num members - num failed - num left)
// This means that we probabilistically expect the cluster
// to attempt to connect to each failed member once per
// reconnect interval
numFailed := float32(len(s.failedMembers))
numAlive := float32(len(s.members) - len(s.failedMembers) - len(s.leftMembers))
if numAlive == 0 {
numAlive = 1 // guard against zero divide
}
prob := numFailed / numAlive
if rand.Float32() > prob {
s.memberLock.RUnlock()
s.logger.Printf("[DEBUG] serf: forgoing reconnect for random throttling")
return
}
// Select a random member to try and join
idx := int(rand.Uint32() % uint32(n))
mem := s.failedMembers[idx]
s.memberLock.RUnlock()
// Format the addr
addr := net.UDPAddr{IP: mem.Addr, Port: int(mem.Port)}
s.logger.Printf("[INFO] serf: attempting reconnect to %v %s", mem.Name, addr.String())
// Attempt to join at the memberlist level
s.memberlist.Join([]string{addr.String()})
}
// checkQueueDepth periodically checks the size of a queue to see if
// it is too large
func (s *Serf) checkQueueDepth(name string, queue *memberlist.TransmitLimitedQueue) {
for {
select {
case <-time.After(time.Second):
numq := queue.NumQueued()
metrics.AddSample([]string{"serf", "queue", name}, float32(numq))
if numq >= s.config.QueueDepthWarning {
s.logger.Printf("[WARN] serf: %s queue depth: %d", name, numq)
}
if numq > s.config.MaxQueueDepth {
s.logger.Printf("[WARN] serf: %s queue depth (%d) exceeds limit (%d), dropping messages!",
name, numq, s.config.MaxQueueDepth)
queue.Prune(s.config.MaxQueueDepth)
}
case <-s.shutdownCh:
return
}
}
}
// removeOldMember is used to remove an old member from a list of old
// members.
func removeOldMember(old []*memberState, name string) []*memberState {
for i, m := range old {
if m.Name == name {
n := len(old)
old[i], old[n-1] = old[n-1], nil
return old[:n-1]
}
}
return old
}
// recentIntent checks the recent intent buffer for a matching
// entry for a given node, and either returns the message or nil
func recentIntent(recent []nodeIntent, node string) (intent *nodeIntent) {
for i := 0; i < len(recent); i++ {
// Break fast if we hit a zero entry
if recent[i].LTime == 0 {
break
}
// Check for a node match
if recent[i].Node == node {
// Take the most recent entry
if intent == nil || recent[i].LTime > intent.LTime {
intent = &recent[i]
}
}
}
return
}
// handleRejoin attempts to reconnect to previously known alive nodes
func (s *Serf) handleRejoin(previous []*PreviousNode) {
for _, prev := range previous {
// Do not attempt to join ourself
if prev.Name == s.config.NodeName {
continue
}
s.logger.Printf("[INFO] serf: Attempting re-join to previously known node: %s", prev)
_, err := s.memberlist.Join([]string{prev.Addr})
if err == nil {
s.logger.Printf("[INFO] serf: Re-joined to previously known node: %s", prev)
return
}
}
s.logger.Printf("[WARN] serf: Failed to re-join any previously known node")
}
// encodeTags is used to encode a tag map
func (s *Serf) encodeTags(tags map[string]string) []byte {
// Support role-only backwards compatibility
if s.ProtocolVersion() < 3 {
role := tags["role"]
return []byte(role)
}
// Use a magic byte prefix and msgpack encode the tags
var buf bytes.Buffer
buf.WriteByte(tagMagicByte)
enc := codec.NewEncoder(&buf, &codec.MsgpackHandle{})
if err := enc.Encode(tags); err != nil {
panic(fmt.Sprintf("Failed to encode tags: %v", err))
}
return buf.Bytes()
}
// decodeTags is used to decode a tag map
func (s *Serf) decodeTags(buf []byte) map[string]string {
tags := make(map[string]string)
// Backwards compatibility mode
if len(buf) == 0 || buf[0] != tagMagicByte {
tags["role"] = string(buf)
return tags
}
// Decode the tags
r := bytes.NewReader(buf[1:])
dec := codec.NewDecoder(r, &codec.MsgpackHandle{})
if err := dec.Decode(&tags); err != nil {
s.logger.Printf("[ERR] serf: Failed to decode tags: %v", err)
}
return tags
}
// Stats is used to provide operator debugging information
func (s *Serf) Stats() map[string]string {
toString := func(v uint64) string {
return strconv.FormatUint(v, 10)
}
stats := map[string]string{
"members": toString(uint64(len(s.members))),
"failed": toString(uint64(len(s.failedMembers))),
"left": toString(uint64(len(s.leftMembers))),
"member_time": toString(uint64(s.clock.Time())),
"event_time": toString(uint64(s.eventClock.Time())),
"query_time": toString(uint64(s.queryClock.Time())),
"intent_queue": toString(uint64(s.broadcasts.NumQueued())),
"event_queue": toString(uint64(s.eventBroadcasts.NumQueued())),
"query_queue": toString(uint64(s.queryBroadcasts.NumQueued())),
"encrypted": fmt.Sprintf("%v", s.EncryptionEnabled()),
}
return stats
}
// WriteKeyringFile will serialize the current keyring and save it to a file.
func (s *Serf) writeKeyringFile() error {
if len(s.config.KeyringFile) == 0 {
return nil
}
keyring := s.config.MemberlistConfig.Keyring
keysRaw := keyring.GetKeys()
keysEncoded := make([]string, len(keysRaw))
for i, key := range keysRaw {
keysEncoded[i] = base64.StdEncoding.EncodeToString(key)
}
encodedKeys, err := json.MarshalIndent(keysEncoded, "", " ")
if err != nil {
return fmt.Errorf("Failed to encode keys: %s", err)
}
// Use 0600 for permissions because key data is sensitive
if err = ioutil.WriteFile(s.config.KeyringFile, encodedKeys, 0600); err != nil {
return fmt.Errorf("Failed to write keyring file: %s", err)
}
// Success!
return nil
}
// GetCoordinate returns the network coordinate of the local node.
func (s *Serf) GetCoordinate() (*coordinate.Coordinate, error) {
if !s.config.DisableCoordinates {
return s.coordClient.GetCoordinate(), nil
}
return nil, fmt.Errorf("Coordinates are disabled")
}
// GetCachedCoordinate returns the network coordinate for the node with the given
// name. This will only be valid if DisableCoordinates is set to false.
func (s *Serf) GetCachedCoordinate(name string) (coord *coordinate.Coordinate, ok bool) {
if !s.config.DisableCoordinates {
s.coordCacheLock.RLock()
defer s.coordCacheLock.RUnlock()
if coord, ok = s.coordCache[name]; ok {
return coord, true
}
return nil, false
}
return nil, false
}
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